Tag Archive | "Dropsy"

Dropsy in Goldfish


Dropsy in Goldfish

Dropsy in Goldfish

Dropsy also known as Malawi Bloat, is a condition that occurs both in holding ponds and tropical fish keeping aquariums that when not treated promptly, is almost always fatal to the fish.   Dropsy is a bacterial fish disease that targets the internal organs causing the accumulation of water in the belly of the fish which is exhibited by swelling of the abdomen and protruding scales.


The most obvious external symptom of Dropsy is the characteristically swollen belly of the fish which means that the internal organs have already been injured.   At this stage, it is unlikely even with prompt medical treatment that the fish will survive.   Other easily detectable symptoms include swollen eyes, pale gills, swollen bloody colored anus, pale feces, clamped fins, a curved spine, and protruding (pine cone like) scales that stand out from the fish.  Although some specimens with Dropsy may not show any visible symptoms, a loss of appetite and lethargic movement with the fish hovering around the top of the tank instead of swimming normally could indicate the early stages of the disease.

All of the above symptoms progress aggressively, which is why early detection is so important to the prevention and spread of Dropsy to other inhabitants of the tank.

If you notice even one of the these symptoms, start treatment immediately.


Dropsy is caused by a common gram negative bacteria called Aeromonas which is present in all aquarium environments and attacks the immune system of the fish.   Although it displays a combination of symptoms that is actually more of a health issue then a disease, Aeromonas can lead to Dropsy only when the immune system of the fish is failing or has already failed.

Decreased immune system stability occurs when fish are under stress, which can be the result of several factors.

  • Poor water quality
  • Changes in Nitrate and Ammonia levels
  • Drastic changes in water temperature
  • Bullying and aggressive behavior
  • Poor or unbalanced diet

When fish in an enclosed system are stressed from anything at all, the immune system will start to fail and the Aeromonas bacteria begin to do their work.   The bellies of the infected fish will start to drop down and appear bloated as the bacteria infects the immune system.  When the swelling of the belly is sudden, the probable cause is probably Aeromonas however, when the swelling is gradual, parasites or cancer could be the culprit.

There is virtually no danger of your fish contracting Dropsy if they are healthy and thriving in a healthy environment without any of the above stress factors.


Treatment for Dropsy depends on how quickly the disease is diagnosed. Most tropical fish keeping enthusiasts euthanize infected fish to prevent healthy fish from being infected, but if you can detect the disease in its early stages, infected fish can be treated successfully.

This is what can be done:

  • Move all infected fish into a bare hospital tank with an air powered sponge corner filter.
  • Change 50% of the tank water in the infected aquarium
  • Monitor healthy fish for symptoms to prevent the further spread of the infection.
  • Add 1 tsp of salt per gallon of tank water to the hospital tank and maintain spotlessly clean conditions by performing weekly 50% water changes.
  • Provide the highest quality food you can acquire to boost the fish’s immune system. When the fish exhibit signs of improvement, maintain the diet until all symptoms are gone.

Most of the time, a healthy diet and immaculate water quality will “perk up” the immune systems of the fish.

  • If the fish still do not show signs of improvement, start treating the infected fish with a good antibiotic like Maracyn 2 or an equivalent. Usually a 10 to 12 day treatment will destroy any signs of Dropsy.

If the fish does not respond favorably after 3 weeks or so, the specimen may need to be humanely euthanized.

KanaPlex, ParaGuard, Furan-2, Melafix, SulfaPlex and several other over the counter bacterial medications also work on Dropsy.


All fish are prone to stress and when stressed over a period of time, their immune systems will eventually fail allowing them to become prey to a variety of diseases.

Like all bacterial infections, the best way to prevent Dropsy is to provide your fish with a clean, healthy, aquarium environment.

We know that a weakened immune system can cause Dropsy in freshwater and marine tropical fish.   This can be because of poor water quality, wide fluctuations in water parameters, constant stress, bullying from tank mates, malnutrition, etc.

Because poor water quality is the number one stress factor for all tropical fish, maintaining a clean aquarium should be the number one priority for all successful tropical fish keeping enthusiasts.

You can prevent Dropsy and virtually all other tropical fish diseases by adhering to the following:

  • Change the tank water on a regular schedule.
  • Clean and replace filter medium on a regular basis.
  • Clean power heads and pre-filters on a regular schedule.
  • Regular checks of Ammonia and Nitrite levels.
  • Avoid drastic changes in water temperature.
  • DO NOT over populate your aquarium.
  • Quarantine new additions to your aquarium.
  • Remove constantly bullied or bullying fish into another aquarium when observed.
  • Be careful about the quality, how much, and how often you feed your fish. Never overfeed.
  • Note the shelf life of prepared fish foods and use within a couple of months of opening or before the expiration date.
  • Provide your fish with a mixed diet of prepared, live, frozen, or freeze dried foods.

Posted in Bacterial Infections, Featured Articles, Tropical Fish Diseases, Tropical Fish KeepingComments (2)

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